#define _CRT_SECURE_NO_WARNINGS 1
#include<iostream>

typedef long long LL;

const int N = 100010;

int n;
int q[N], tmp[N];

using namespace std;
LL merge_sort(int l, int r)
{
	if (l >= r)
		return 0;
	int mid = (l + r) >> 1;
	LL res = merge_sort(l, mid) + merge_sort(mid + 1, r);
	int k = 0, i = l, j = mid + 1;
	while (i <= mid && j <= r)
		if (q[i] <= q[j]) tmp[k++] = q[i++];
		else
		{
			tmp[k++] = q[j++];
			res += mid - i + 1;
		}
	while (i <= mid) tmp[k++] = q[i++];
	while (j <= r) tmp[k++] = q[j++];
	for (int i = l, j = 0; i <= r; i++, j++)
	{
		q[i] = tmp[j];
	}
	return res;
}
int main() 
{
	cin >> n;
	for (int i = 0; i < n; i++) cin >> q[i];

	cout << merge_sort(0, n - 1) << endl;
	
	return 0;
}